It is accepted that dynamic loads and structural responses must be analysed in design of large offshore structures. Recent studies in Europe and Japan have shown that it is unsafe to ignore high intensity short duration loads in design of caisson breakwaters and related harbour structures. Dynamic effects of wave loads are however seldom included in structural analysis of coastal structures, leading to designers ignoring short-duration wave loads, perhaps contributing to damage to a range of breakwaters, seawalls or suspended decks. This paper reports recent advances in knowledge on impulsive wave loads, describes analysis for dynamic responses, and illustrates a range of prediction methods to include these important effects in design. It compares measurements of impulsive and pulsating loads from physical models of coastal structures, to quantify their magnitude and relative importance.